The person who has everything is not difficult because they are rich. They are difficult because they are finished. Every need has been met, usually by them, usually better than you would have met it. Buying them something useful is a losing game: whatever you choose, they own a nicer one.
Which leaves exactly one opening. Give them something with no use at all, executed to an unreasonable standard. Uselessness is the only category they have not already optimised.
You cannot out-equip someone who has everything. You can only out-commit them to something pointless.
One
The Art of the Unread Book
The correct gift for someone who does not read, because it is explicitly about not reading. A serious treatise on owning a library that speaks well of you without ever opening it — shelf arrangement, spine selection, the strategic bookmark left at page 212. They will put it on the shelf. The book predicted this on page nine.
Buy on {store}Two
Cats and Civilisation
Our heaviest and handsomest title: an exhaustive account of who has really been in charge since 3000 BC. Forest-green cloth, foiled spine, entirely straight face. If they own a cat it is a tribute. If they do not, it is a warning.
Buy on {store}Three
A candle that smells like a library
Leather, cedar, a little dust. The person who has everything has, we guarantee, at least four candles — but none of them smells like a room they aspire to own. Burns for fifty hours and makes a very ordinary sitting room briefly convincing.
Find it on {store}Four
A Short History of Bad Ideas
Four thousand years of confident decisions, arranged chronologically and footnoted without mercy. Excellent for the friend who is always three weeks into a new venture. It can be read as history or as a hint, and the beauty of it is that you never have to say which.
Buy on {store}Five
A fountain pen they will never use
The archetypal gift for the finished house. It will be admired, filled once, and kept in a drawer with the good scissors. This is not a failure. Some gifts are for using and some are for owning, and the person who has everything already knows the difference.
Find it on {store}Six
Replying Later: A Memoir
Nine hundred unanswered messages, annotated by the man who did not answer them. A universal gift, in that it describes everyone, and a pointed one, in that it describes some people considerably more. Best given without comment.
Buy on {store}Seven
The Domestic Affairs cover pack
Nine printable covers on housework, houseplants and household diplomacy, including Whose Turn It Actually Is. Print one, wrap it round a book already on their shelf, and say nothing. The best gift for a finished house is a small, deniable act of vandalism.
Buy on {store}Eight
The Blank Template Kit
Six editable cover layouts in the house style. Put their name on the spine, invent a title that only the two of you will understand, print it, and you have made something that genuinely does not exist anywhere else. Unbeatable against a person who owns one of everything.
Buy on {store}The rule
When someone has everything, stop trying to be useful and start trying to be specific. A gift that could have been for anyone will be absorbed into the house without trace. A gift that could only have been for them — and could only have come from you — survives the cull in January.